It is known that the standard lithium niobate Mach Zehnder switch has two voltage ports. The first is an RF port to apply short voltage pulses and the second is a DC port to apply the appropriate DC bias voltage. The DC voltage usually sets the switch for minimum throughput when no voltage is applied to the RF port.
The DC voltage for minimum throughput drifts over time and temperature. It is known that application of a small dither voltage to the DC port, and the use of a hill climb servo, can be utilized to find the optimum DC bias point. Since this technique introduces excess noise into the system, it is desirable to find a better method.